Retirement Plans Retirement Plans Level 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used in Calculation, Description	0.5
Defined Benefit Plan, Interest Cost	$ 923	$ 1,067	$ 1,179
Defined Benefit Plan, Amortization of Gain (Loss)	(1,127)	879	259
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(204)	1,946	1,438
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	28,681	30,078
Defined Benefit Plan, Interest Cost	923	1,067	1,179
Defined Benefit Plan, Actuarial Net (Gains) Losses	(1,127)	879
Defined Benefit Plan, Benefit Obligation, Benefits Paid	3,770	3,343
Defined Benefit Plan, Benefit Obligation	24,707	28,681	30,078
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Plan Assets, Amount	0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer	3,770	3,343
Defined Benefit Plan, Plan Assets, Amount	0	0	$ 0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(24,707)	(28,681)
Defined Benefit Plan, Accumulated Benefit Obligation	24,707	28,681
Liability, Defined Benefit Pension Plan, Current	(3,175)	(3,265)
Liability, Defined Benefit Pension Plan, Noncurrent	(21,532)	(25,416)
Liability, Defined Benefit Pension Plan	(24,707)	(28,681)
Defined Benefit Plan, Estimated Future Retirement Benefits Covered by Insurance Contract, Amount	47,100	46,500
Cash Surrender Value of Life Insurance, Retirement Plans	$ 37,200	$ 36,400
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.13%	3.41%	3.76%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.26%	3.86%	3.96%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	0.00%
Year One	$ 3,175
Year Two	2,728
Year Three	2,398
Year Four	2,319
Year Five	2,073
Years 2024 through 2028	8,622
Defined Contribution Plan, Cost	36,800	$ 33,200	$ 32,500
Defined Benefit Plan, Plan Assets, Benefits Paid	$ 3,770	$ 3,343